A California College Student Had Just Finished Her Work Shift. Then, She Disappeared in Broad Daylight.

She had just finished her shift at a coffee shop when she began speaking to a blonde woman inside the business. Then, she was gone in broad daylight.

That June 23, 1997, day was the last time anyone has seen college student Kristen Modafferi, of San Francisco. She was 18 years old then and would be 45 years old now.

Her family is still holding out hope that they'll get answers in the baffling case.

"When I think about 20 years having gone by, I feel quite robbed on having missed out on the experience and Kristen not being here, part of our family, for the beautiful milestones in our lives," Lauren Modafferi, Kristen's sister, told ABC News 7 as she choked back tears in 2017.

The case is considered one of the most perplexing ones in San Francisco history. In 2017, private investigators had some sense of hope when they found new evidence and a possible DNA match.

However, she's still not been found.

"I never thought it was going to be this long," Dennis Mahon, a friend of the family who's been searching for her, told sfgate.com in 2018. "I always thought that I was going to run into somebody who knew her or the cops were going to find her or she was going to show up somewhere.

"I remember in the early days, it was, 'OK, I just stay another week, I'll just stay another week.' The next thing you know, the months and the years just accumulated."

Modafferi and her family were originally from the Charlotte, North Carolina area before Kristen moved to Oakland, California in the summer of 1997 to take a photography class at UC Berkeley.

The family never could have known that having their loved one go coast to coast would lead to her disappearance.

"We think about her all the time," Allison Modafferi said in 2017.

Much mystery surrounds the blonde woman who Modafferi was believed to have been seen with before disappearing.

"As far as who that could be, we're just not sure," her father, Bob Modafferi, said in 2017, the 20-year anniversary of her disappearance.